I ended up not staining it and just went with varathane water based and lots of it...
Thank you for pointing that post out though I would have never thought of beeswax. Maybe I'll polish it with beeswax after just to be on the safe side.
Here's the progress so far. I removed most the glass, shelves and hardware, sanded and filled the wood, as well as repaired the door (its slightly cracked so it wasn't fitting into the door frame properly), 2 coats of varathane (probably going to do 1 or 2 more).

Still undecided what to do about ventilation.
1) Drill holes in the top and back. Wasn't sure if this was a good idea being cedar. Would I need to finish inside the holes?
-Or-
2)Replace the glass door with a screen. Wouldn't be as pretty but would also lighten the door up. I'm worried about putting the glass back in the frame, I'm pretty sure the weight or the glass combined with the softness of the wood is what damaged it in the first place. Here's some pics of the door mess so you can see what I'm dealing with .


That L bracket thingy was our repair to try and pull the cracked wood back together and straighten out the door. There's one in each corner. Between the bracket and the hinge there's a huge crack that I filled with wood glue but its still kinda warped.